Pomadasys maculatus

Diagnostic characters. Meristics: D-XII, 14; P 1 - 17; P 2 - I, 5; A-III, 7; C- 18 Body compressed; head blunt and dorsal profile convex; mouth small and slightly oblique; maxilla reaching to eye; narrow bands of small pointed teeth in the jaws. Scales ctenoid, moderate; present on head excluding snout. Chin with two pores and a median pit. Lateral line slightly arched. Body color silvery white, nape and back with a series of incomplete variable cross bars on the upper half of the body; spinous dorsal fin large with black blotch; dorsal and caudal fins edged with black, other fins yellowish (Fig. 3 c).

Sumber: Grunts (Actinopterygii: Perciformes: Haemulidae) of Bangladesh with two new distributional records from the northern Bay of Bengal assessed by morphometric characters and DNA barcoding

Genetic description. We successfully barcoded six of the seven collected grunt species viz. Plectorhinchus macrospilus, Plectorhinchus pictus, Pomadasys andamanensis, Pomadasys argyreus, Pomadasys guoraca, and Pomadasys maculatus, and submitted to GenBank (NCBI) and BOLD system. The COI sequences of Plectorhinchus macrospilus, Pomadasys andamanensis, and Pomadasys guoraca were submitted for the first time to GenBank as reference DNA barcode sequence. We identified 11 COI barcode sequences of 6 species. For Pomadasys argenteus, we were unable to obtain a clear sequence. Sequence alignment of COI gene yielded about 602 nucleotide base pairs after removing the ambiguous sequences near primer ends. The COI sequences of 11 individuals of 6 species comprised 11 haplotypes with 174 polymorphic sites. The estimated mean ratio of transition and transversion was 2.88. The sequence analysis revealed that the mean nucleotide compositions in 11 COI sequences of 6 species were A = 22.5 % + / - 0.52 %, T = 28.11 % + / - 0.59 %, C = 30.45 % + / - 0.63 %, G = 18.95 % + / - 0.71 %. The overall GC content was 49.39 %. The nucleotide diversity was calculated as 0.134 and the haplotype diversity was 1.0 for the sequences. The mean interspecific distance was 23.4 % among the six species studied. The overall genetic distance among the sequences of COI gene was 16.3 %. Among the six grunt species of the presently reported study, the highest pairwise genetic distance was found as 23.36 % between Plectorhinchus pictus and Pomadasys argyreus, and the lowest distance (9.9 %) was found between Plectorhinchus macrospilus and Plectorhinchus pictus. In the phylogeny, we used 11 COI sequences of six species obtained in the presently reported study and three other sequences of Pomadasys maculatus, Pomadasys argyreus, and Plectorhinchus pictus retrieved from GenBank. The phylogenetic tree showed six clades, each belonging to the separate species (Fig. 4). No valid conspecific sequence of Plectorhinchus macrospilus, Pomadasys andamanensis, and Pomadasys guoraca was found in GenBank for comparison. However, the COI sequence of these three species clearly formed three separate clades from other species of grunt in the constructed ML tree with over 90 % bootstrap value.